Soil Biodiversity Indicators

Wien

2005

S. 19

Artikel aus einer ZeitschriftUnselbständiges Werk

200123321

"Loss of soil biodiversity" is listed as one of the eight major threats in the EU Soil Thematic Strategy. However, in scientific circles it is debated, how to concisely measure this parameter. Soil biodiversity is tremendous and many organisms are still unknown. Nevertheless, potent tools for monitoring the species richness and abundance of soil microbiots and fauna have been developed in recent years. Within the project "MOBI-e: Development of a Concept for Monitoring Biodiversity in Austria" (http://www.ebundp.at) we have reviewed the literature and international soil monitoring programs for biodiversity indicators. Pemising molecular methods such as TRLFP-analysis and microarrays for soils are rapidly developing. However, so far there is no experience in applying these tools in countrywide soil surveys. Classical methods such as soil respiration, microbial biomass and nitrogen mineralization have been proved valid in this context. They provide information about the activity of soil organisms but only little about species richness and abundance. Therefore we suggest the inclusion of more specific biodiversity indicators such as PLFA-markers (Phospholipid Fatty Acids) in monitoring programs. For this purpose we have adapted the classical method which involves a time-consuming extraction procedure to a more simple method, which allows a higher sample throughput. The method relies on the analysis of cell membrane components which can be assigned to groups of soil organisms, such as protozoa, mycorrhizal fungi or gram negative bacteria. Concerning soil fauna the discussion is still ongoing, and it has to be decided which group of organisms is most viable as a representative of biodiversity. Collembola have been used in monitoring programs, as they occur in most soils across different landuse practices. Other authors suggest the use of earthworms in neutral soils and enchytraeids in more acidic soils. The latter have the advantage, that there is an exisiting system of annelid coenoses which can be used as reference data. Another suggestion is the use of oribatid mites, which are easily determined and occur everywhere. Within the project cluster "DIANA - Diversity in Austrian Natural Forest Soils" we try at the moment to find out, which of these faunal groups have the strongest representative value for overall soil biodiversity in forest soils.